ahō no Mako-chan is a Japanese anime series by Toei Animation. The story is loosely based on the Hans Christian Andersen tale The Little Mermaid. The series has been dubbed into various languages including French, Spanish, Polish and Italian. It is also often known as Mako the Mermaid, Mako-chan’s Magic, Syrenka Mako and Magical Mako-chan.

Mahō no Mako-chan aired in 1970 via Nippon Educational TV, which is now TV Asahi.

Overview from themoviedb.org